One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,6)(3,7,8,5)(10,14)(11,17)(16,21)(19,23)(25,26)(27,30)(28,31)(29,34)(32,37)(33,35)(36,39)(38,40)(41,42)(43,46)(44,52)(45,48)(47,53)(49,51)(50,55)(54,56)(3,8)(5,7)(10,14)(11,17)(12,20)(22,24)(26,27)(28,35)(29,37)(38,39)(41,42,45,48)(43,49,51,46)(44,47,53,52)(50,55,56,54)(9,10)(11,18)(12,16)(13,14)(15,17)(19,24)(20,21)(22,23)(25,27,30,26)(28,33,35,31)(29,32,37,34)(36,38,40,39)(41,42)(43,49)(44,52)(45,48)(46,51)(47,53)(50,54)(55,56)(1,3)(2,5)(4,8)(6,7)(9,11)(10,15)(12,19)(13,17)(14,18)(16,22)(20,23)(21,24)(25,28)(26,31)(27,33)(29,36)(30,35)(32,38)(34,39)(37,40)(41,43,45,51)(42,46,48,49)(44,50,53,56)(47,54,52,55)(1,2)(3,5)(4,6)(7,8)(9,12)(10,16)(11,19)(13,20)(14,21)(15,22)(17,23)(18,24)(25,29,30,37)(26,32,27,34)(28,36,35,40)(31,38,33,39)(41,44)(42,47)(43,50)(45,53)(46,54)(48,52)(49,55)(51,56)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.